I have a 93 ex. It has had the check engine light on since i bought it about a year ago. The guy I bought it from said the shop he took it to said it was a vacuum leak he thought. I've tried some of the checks in my Haynes repair manual, and can't figure it out. I was just wondering if there are any common problem spots, any hoses **** to cracking, or something getting plugged or anything like that. thanks

 

Having the check engine light means the engine computer (ECU) has detected a problem and stored a code.

That code will identify what sensor, etc is causing a problem. You need to get the code and post the code on here. We can give you more details on what is wrong once we get that code.

It is pretty simple to retrieve a code.

There is a blue two pin connector behind the passenger's side kick panel. Use a piece of wire or a thin paperclip to jump that plug. Turn the key to the II position (don't start the car) and count the check engine light flashes. A long blink =10 and a short blink =1. So L L L S = 41. If there is another code, there will be a pause after the first code, then it will flash the second codes. It will repeat flashing the codes so you can double check. You can also turn the key off then back to the II position to have the codes flashed again.

Here is a site with a picture and some information.

http://www.techautorepairs.com/dtc.html

 

thats weird the code was 41. the website you posted says primary oxygen sensor heater. Is that correct? i notice it says "generic" at the top, so I'm not sure. I assume that the primary is the one just before the flex pipe. thanks

 

I must be psychic?
You only have one O2 sensor on your car, and it is right before the catalytic converter.

If you have a volt meter, unplug the sensor and check the resistance between the C and D pins (they should have the same color wire). If it has 10-40 ohms, then we can further troubleshoot the problem. If the resistance is infinite (open circuit), replace the O2 sensor. I attached a pic to help.

Someone mentioned on here that the aftermarket Denso O2 sensor is the same thing you will buy at a honda dealership for much less money.

 

yeah its right before the flex pipe which is right before the catalytic converter. I noticed it during all the time i just spent underneath replacing the clutch and CV shafts. I wasn't sure if there was one downstream after the cat also, I've never noticed. Thanks for the help, it's much appreciated. I will check it out tomorrow, and let you know if I have any more trouble.

 

The 2nd sensor is in the cat (not after) and it didn't show up until 1996.